Varroa mite control

Hi Margaret -
A while back I asked some questions about varoa mites and less toxic
approaches. A number of people mentioned wintergreen and spearment oils and
plants as options. Below are some excerpts of the answers I got; hope you
find them useful. (Thanks again to everyone who answered my request for
info!)
Patricia Dines
Note: One thing I personally would do is check is if there are pesticide
applications going on in their range. There's a growing body of evidence
that pesticides can weaken the immune systems of animals, making them more
vulnerable and less able to protect themselves. I also wonder what the
natural enemy is their native land - could that be imported? Or a similar
native here be encouraged....?
---- EXCERPTS ----
From: robert Dixon, INTERNET:rdixon@citrine.cyberstation.net
I have worked as an organic inspector doing honey inspections in
northern Alberta Canada. The varroa mite was just a rumor at that stage but
one beekeeper that had applied for certification moved his hives south to
overwinter them. The law required that he use Apistan (fluvalinate is the
active ingredient) so I had to read up on this product. The information
from Agriculture Canada said that it was a synthetic pyrethroid and as such
it was extremely toxic to non target insects and also aquatic life. There
were warnings about how to dispose of the strips after it had been used.
The information from the governement also revealed that little study had
been done about how it breaks down in nature, what it breaks down into and
how persistent it is in the environment. It did not seem to me to be a very
organic product for the above listed reasons.
The varroa mite is a blood sucking parasite that originally came
from the east as far as I know. It gets into the brood cells where it
destroys the next generation and can spread very quickly within a hive.
Beekeepers are advised to check their hives using Apistan strips to see if
any show up before deciding to treat them. I have read that the African bee
seems to be more resistant to the varroa mite because of it's aggressive
grooming habit. An alterantive treatment for varroa is to use formic acid.
There are several problems with this more environmentally benign product
including possible damage to the queen bee and difficulty getting control
because it evaporates too quickly in the hive.
An interesting alterantive was mentioned in the recent issue of the
Rachel Carson council newsletter # 88. -" Beekeepers in Cumberland, MD have
been successfully reducing varroa mites in their colonies by using mixtures
of wintergreen and spearment oils. Bees appear not to be adversely affected
by the natural mint oils..."- The suggestion in the article is that bee
foraging areas be seeded with some plants of the mint family so the bees
can forage on them and take the bennefits back to the hive with them.
Menthol is currently used to control tracheal mites in bees.
===
From: "Malcolm (Tom) Sanford, Florida Extension Apiculturist",
INTERNET:mts@GNV.IFAS.UFL.EDU
> 3) Do you know of any studies that examine why the varolla mites became
such a
> problem in the first place? As I recall, they were an exotic (foreign)
mite, at least in the U.S. Is that true? If so, where do they come from?
Do they have no natural predators anywhere in the world?
[Varroa jacobsoni]... was introduced as an
exotic pest onto Apis mellifera from a closely-related bee Apis cerana.
Apis mellifera, the European honey bee has no natural tolerance for this
mite; almost every infested colony is killed. In the U.S. and elsewhere
where Varroa is found, many wild honey bee colonies in trees, houses, etc.
have been killed. It is sort of like AIDS in humans in this sense..
> One theory I have is that pesticides perhaps knocked out the natural
> mite/predator balance that would've kept them in check. (I'm thinking
this
> because of a conversation I had once with an apple farmer who said they
stopped
> using mitacides and stopped having problems with mites - he said, because
the
> broad-spectrum mitacide was killing both the good and bad mites. (He also
> nurtured his trees more.)
This is true for a healthy farm eco-system, but has not been shown in the
case of Varroa. There appear to be no natural Varroa enemies in a beehive.
) Another theory I have is that pesticides might've
> weakened the bees and made them more vulnerable than they otherwise
would've
> (because many pesticides harm bees, including weakening them).
This is a possibility. Chronic exposure of bees to low-levels of
pyrethroids may be harmful but has yet to be shown.
===
From: Bob MacGregor, INTERNET:RDMACGREGOR@gov.pe.ca
<snip>
By the way, I am by no means an expert on bees (try the bee site at Ohio
State U. or the BOMBUS news group, or Forgotten Pollinators
[referenced in a recent PANUPS release])
===
From: Kenny W Bailey, INTERNET:kbailey@cumberla.ces.state.nc.us
To: Patricia Dines, 73652,1202
Cc: kbailey@cumberla.ces.state.nc.us
Date: Wed, Dec 4, 1996, 8:29 AM
Subject: Re: World's Beeswax Contamination Increasing
<snip>
First of all, there are two mites that are causing significant problems in
honey bees, the tracheal mite and the varroa mite.<snip>
The varroa mite is a much larger mite. It can be seen, on the body of the
honey
bee, with the unaided eye. This mite feeds on the honey bees blood. At this
point in time, fluvalinate impregnated strips under the brand name
"Apistan",
is the only labeled treatment in the U.S. for varroa mites. Menthol will
not
control the varroa mite <snip>
I'm going to limit my discussion, now, to the varroa mite because in my
area of
North Carolina, it seems to be the most devestating of the two mites. I
also
have first hand experience with losses of honey bee colonies from the
varroa
mite. I lost nearly half of my hives to varroa mites this year, due to
lack of
treatment. Several of our beekeepers have also given up on beekeeping
because
of varroa mite.
The varroa mite is a native parasite of the Asian Honey Bee. The Asian
honey
bee is a completely different species from our European Honey Bee. The
varroa
mite can parasitize the Asian honey bee without killing its host. The
European
honey bee was not exposed to the varroa mite until European honey bees were
taken to Asia and came in contact with the Asian honey bee. The varroa mite
jumped onto these European honey bees and became a parasite of the European
honey bee. The Asian honey bee and the varroa mite evolved together and
have
had a parasitic relationship for a much longer time than the European honey
bees have been exposed to varroa mite. The European Honey bee cannot resist
these mites as the Asian honey bee does, therefore, the result of the
relationship between the varroa mite and the European honey bees are dead
European honey bee colonies.
To address the question about predators of these mites, keep in mind that
the
European Honey Bee is not native to the United States nor are the varroa
mites,
so the likelihood of there being natural predators of the varroa mite here
in
the U.S. at this time, is very slim. There may be some natural predators of
the
varroa mite in Asia, but someone else would have to answer that question.
Patricia, the varroa mite problem is a very serious one and it needs more
attention. The population of beekeepers in this world is very small, but
the
entire world depends upon the honey bee for about one-third of its food
supply,
through the pollination of crops. We need more research into this problem
or we
are going to be in a lot of trouble. We need to find more and better ways
of
controlling this pest.
===
From: Bob MacGregor, INTERNET:RDMACGREGOR@gov.pe.ca
Many modern farming practices limit habitat for native bees by being too
"clean". Also, of course, the pesticides used can really zap the natives
(since no one is going to move their colonies elsewhere until the sprays
have dissipated!).
===
From: Pesticide Watch, INTERNET:pestiwatch@igc.org
Apistan (active ingredient t-fluvalinate) is a pyrethroid. Tox Class 2.
[PD NOTE: Tox Category 1 is the most acutely harmful, 4 the least of those
with toxicity.]
===
FROM: Jose Villa
I work with the USDA-ARS in research with honey bees. There is a lot of
concern and discussion among researchers and beekeepers about the misuse
of miticides, development of resistance (is already documented in Europe),
and contamination of bee products. ... Ultimately
everyone hopes to have European bees that have similar resistance
mechanisms
to those of Asian honey bees. There is some progress in Europe and the
U.S.
in this area, but until then beekeepers will have to use some natural or
artificial chemical to keep their colonies from dying.